| 摘要 |
PURPOSE:To attain remarkable man-hour reduction and cost reduction by forming an ''Invar'' flat bar into round shape, forming a round pipe by seam welding and drawing this round pipe so as to form a rectangular waveguide. CONSTITUTION:First the ''Invar'' flat bar 1 is formed into round shape, the seams 3 are welded to form the ''Invar'' welded round pipe 2. Then, the pipe end of the round pipe 2 is squeezed by a hydraulic press so as to form the pipe end of the round pipe 2 into a flat trigger. Then, the flat trigger is passed into a roller die of parallel rolls and the trigger is drawn by a chain type drawing machine. In taking the pitch of the parallel rolls as a larger size than a short side of the final rectangular shape slightly in this case, an intermediate square pipe 4 having a slightly larger diameter than that of the final rectangular pipe is formed. The residual stress is eliminated by applying heat treatment to the intermediate square pipe 4, a lubricant is coated, then drawing is executed by a conventional drawing machine. Thus, the ''Invar'' rectangular waveguide 5 is obtained. Remarkable man-hour and cost reduction are attained by this method. |
